Flaked sulphur dyes



Patented Apr.

UNITED ,STATES PATENT orncs 2,037,005 FLAKED SULPHUR- Dims William s. 0mm, Penns'grove, N. 1., nerbren.

Lubs, Wilmington,

Woodbury, N. J., assignors to E.

DeL, and George Barnhai-t-, N

I. du Pont de Nemours & Company, Wilmington, Del., a corporation oi Delaware No Drawing. Application May 4, 1932, Serial No. 009,200

1 Claim. (0 86) This invention relates to organic compounds thionation is carried out at elevated temperatures in water or alcohol solution. At the end of the reaction the dye is introduced'into'water and liberated by precipitation and filtration. The dyestuffs of this class known to prior art are amorphous and so diflicultly soluble in water that it is usually necessary to incorporate a solubilizlng agent before they can be used for dyeing.-

It is an object of this invention to produce sulphur dyes which are in the form of flakes, are

non-dusting. and dissolve readily in water. A further, object is to produce sulphur dyes in the form of vitreous, stable particles of great strength and density. A still further object is to produce sulphur dyes in the form of flakes, grains, platelets or scales which do not contain appreciable amountsof free sulphur. Additional objects will appear hereinafter.

These objects are accomplished by the present invention which, generally stated, involves removing the ireesulphur in the dyestutf, suspending the dyestuii in a suitable medium, incorporating a binding agent, and drying the mixture preferably inalayer.

The invention will be more completely understood by a consideration of the following examples:

Example 1 Sulphur brilliant green.--The thionation mass obtained by the fusion of the indophenol made from 1 part of phenyI-perLacid, and para-amidephenol, was diluted with 10 parts of water, and 3 parts of. sodium sulphite were added to react with any free sulphur. The solution was then heated to 85 C. and the color precipitated by passing air through the solution. The dyestuff was filtered ofi, suspended in 0.5 part water, and 0.25

- part of 30% sodium sulphide and 0.5 part of black-strap molasses added. The viscous mass was dried on an atmospheric drum dryer. Wa-. ter-soluble flakes, with a metallic sheen were obtained.

' Example 2 4 Sulphur navy blue.--The thionation mass resulting from the fusion of 1 part of an indophenol, made by coupling orthotoluidine with paraamido-phenol, with an aqueous polysulphide con taining 1.4 parts of sodium sulphide and 1.4 parts of sulphur, was diluted with 25 parts of water, 5 e

and 2.5 parts of sodium sulphite were added to react with any free sulphur. It was then heated to 80-85 and the dyestuff precipitated by passing air through the solution. The dyestufi was then filtered off and washed on the filter with water.

It was then suspended in 1 part of water and 0.4 part of 30% sodium sulphide and 0.4 part of black-strap molasses added, and the mass stirredto a smooth colloidal suspension. The mass was then dried on an atmospheric drum dryer. Glistening blue-black, water-soluble flakes were ob-' tained.

Example 3 Sulphur blotch-The mass obtained by the thionation of 1 part of dinitrophenol with an aqueous polysulphide containing 1 part of sodium sulphide g and 1.1 parts of sulphur, was diluted with 5 parts of water, 1.5.parts of sodium sulphite were added to react with any free sulphur, the whole heated to '70 C. and the dyestufi precipitated by passing air through the solution. The dye was filtered ofi and washed on the filter with 4 parts of 10% sodium chloride solution. The washed filter cake was then slurried in 1 part of water, and 0.4

part of 30% sodium sulphide and 0.3 part of preservers syrup added andthe mass stirred to a smooth suspension. It was then dried on an atmospheric drum dryer heated with steam at 30-60 lbs. per square inch pressure. sulphur black was scraped from the revolving drum in'the form of black, glistening flakes, which were directly soluble in water.

Example 4 Sulphur broum.0ne (1) part of meta-tolulylene diamine was fused with 3 parts of sulphur for 20-24 hours at 250-260 C. The resulting thionation mass was extracted with '10 parts of 30% sodiumhydroxide for about 1 hour at the 5 boil to remove free sulphur from the dyestufi, then diluted with 10 parts of water and the dyestuii precipitated by passing air through the solution. It was then filtered and the filter cake mixed with 1.5 parts of 30% sodium sulphide and 0.3 part of preservers syrup, and the mass dried on an atmosphericdrum dryer. Glistening, greenish-black, water-soluble flakes were obtained.

The above examples are inc uded merely for The dried 35- dye.

limit, in any way, invention, since it may be applied to any sulphur If the full advantages of this invention are to be obtained, the dyestuil should be substantially freed from uncombined sulphur and must contain a binder. Although it is advisable that there should be no free sulphur present in the mass which is to be dried, the presence of very small amounts of free sulphur does not entirely obviate the advantages of the invention. It is advantageous to dry the product in a thin layer, and for this purpose a drum dryer is well suited.

The material used is suspended in a suitable medium. Such a medium may be a binder, water,

and sufiicient alkali metal sulphide to render the dried product directly soluble in water. The

suspension is then dried in layers. The particular method of drying may vary according to the material used and the equipment available.

However, very satisfactory results have been obpurposes of illustration and are not intended to the applicability of the present I The present invention produces a product which is characterized by its ready solubility in water; it is vitreous, non-dusting, and extremely stable. The particles produced may be stored for very long periods of time without any noticeable deterioration. .The particles are produced in the form of flakes, scales, grains or platelets which may be mechanically handled without breaking or dusting. They do not contain appreciable amounts of free sulphur so may be used'tor dyeing material without danger of producing sulphur spots or the bronzy eflect usually noticed on material-colored with sulphur dyes.

As many apparently widely different embodiments of this invention may be made without departing from the spirit and scope thereof, it is to be understood that we do not limit ourselves to the specific embodiments thereof except as defined in the appended claim.

We claim:

The method of making a sulphur dye'stuif in flake form which includes reacting a thionation mass at elevated temperature with sodium sulphite in water, removing the dyestuif from the solution byv precipitation and filtration, mixing the dyestufi with molasses, sodium sulphide, and

enough water to make a viscous mass, and drying on a drum dryer.

HERBERT A. LUBS. GEORGE BARNHART.

WILLIAM S. CALCO'IT. 

